Reducing polluting emissions from gas-fired water heaters, such as NOx emissions, continues to be an important objective. Governmental regulations in connection with NOx emissions continue to become more stringent and it has been a longstanding objective in the industry to continue to reduce NOx emissions to the point of ultra-low NOx emissions, such as 10 Ng/J or even less.
Water heater manufacturers have, over the years, attempted to reduce NOx emissions through a variety of approaches, one approach utilizing radiant screen-type burners. One example is the radiant screen-type burner disclosed in U.S. Pat. No. 5,317,992. However, there have been a series of problems associated with simultaneously achieving: 1) the low NOx goal, 2) providing a burner that is resistant to build up of lint, dirt, oils and the like or that can shut itself off when too much of a build-up occurs, 3) being able to manufacture a gas-fired water heater in an economical fashion and 4) to produce a water heater that is safe, has excellent longevity and is noise free upon either initial ignition of the burner or during continued combustion on the burner. To date, such efforts have not been completely successful.